This invention relates to a cartridge for supplying developer powder for use in an electrographic reproduction machine.
In machines employing electrogaphic reproduction techniques developer powder is used to form the darkened image of the information being reproduced. This developer powder consists of microscopic toner particles which through various techniques, as for example, electrostatic charging, can be influenced to attach themselves to a photoconductive surface. This photoconductive surface is then further processed to result in a finished copy. The supply of developer powder or toner is consumed as these particles are utilized in the electrographic reproduction process and hence must be replenished. This replenishing can be very problematic due to the microscopic size and tendency of the toner to become electrostatically charged. It is quite common with the conventional toner supply cartridges to have toner escape during the replenishing process and soil the adjacent areas of the machine as well as the operator and the surrounding office environment. One attempt to solve this problem is disclosed in U.S. Pat. No. 3,999,654, issued to M. A. Pollack. This patent discloses a cartridge for dispensing the toner into the copy machine, in which the opening used for dispensing is closed off by an adhesive tape affixed directly to the wall portions of the cartridge. The adhesive tape terminates in a tab portion which can be pulled after the cartridge has been inserted into the copy machine to release the developer powder. Although the device described by Pollack diminishes the amount of developer powder escaping from the cartridge during its intended release, it still relies strictly on an adhesive tape seal in forming the closure. Since the adhesive surface of the tape is directly exposed to the toner particles, it transports a layer of toner particles which have adhered to its adhesive surface, when it is removed. This toner covered tape is difficult to handle without further soiling the machine or its operator. This type of seal is also inherently prone to release as, for example, due to external mechanical stresses being applied against the surface of the adhesive tape during shipment or handling, causing it to slip or release its contact with the container, resulting in the developer powder escaping from the container.
There is an additional problem with this type of container during the initial toner filling operations. If the same opening is used for dispensing the toner particles, as well as filling the cartridge, the opening must be of an adequate size to afford the dispensing of all of the toner particles within the cartridge. In order to use this cartridge in an automatic filling operation the entire excess of this larger than required filling opening would have to be closed off to prevent the toner particles from escaping during the filling operation. This necessitates greater complexity of the device used to orient the cartridge within the filling machine as well as increased complexity within the filling machine itself.
Similarly, if a second smaller opening for filling the cartridge is provided but is not centrally located, or if the cartridge lacks symmetry with respect to the opening, greater complexity in the machine and its associated handling equipment will result.